The present invention relates to a sacral support saddle for a spinal osteosynthesis device.
It is known that obtaining a firm sacral support in spinal osteosynthesis remains a problem which has not as yet been solved. The bone of the sacrum is, in fact, for the most part spongy and porous, especially in older subjects, and therefore has a low strength. To date, use has been made of a single screw positioned at S1 (first vertebra of the sacrum), in which the lower end of the rod of the corresponding device is inserted, the other screws being driven into the two lumbar vertebrae adjacent to the sacrum. However, the low strength of the sacrum and the considerable leverage arm exerted on the screw develop stresses which result in risks of pulling out the screw.
When such a pulling out takes place, it is then necessary for the surgeon to conduct a second intervention, generally involving the positioning of a second screw at S2 (second vertebra of the sacrum). The device thus becomes bulky. Moreover, this second surgical intervention can entail neurological risks on account of the presence of nerves at S2, and it is more substantial than the preceding intervention and is psychologically poorly received by the patient.